| Objective Through computer-aided technology and 3D printing technology,an individualized navigation template for the best trajectory of upper cervical pedicle screw placement is designed and printed,which is applied to assist pedicle screw placement in upper cervical spine fracture/dislocation surgery.The accuracy and application effect of the two methods were evaluated by comparing with the freehand nail placement.Methods Twenty patients with upper cervical spine fracture/dislocation who were treated in our department from June 2009 to June 2019 were selected and divided into two groups according to different surgical methods.Preoperative examinations such as cervical spine three-dimensional CT,cervical spine MRI,cervical spine frontal and lateral view,and cervical spine opening position were perfected in all patients.Among them,7 patients in the control group were implanted with pedicle screws in the upper cervical spine by traditional screw placement.In the guide plate group of 13 cases,the preoperative three-dimensional CT data of the cervical spine was imported into the computer software to independently design the best atlantoaxial pedicle screw channel,and the individualized navigation template to assist the pedicle screw placement was designed on the computer using the principle of reverse engineering.,using 3D printing technology to print a solid 1:1 scale cervical vertebra model and a guide template to simulate the screw placement experiment to verify the feasibility of the guide plate and then assist in the placement of upper cervical pedicle screws.The control group included 5 males and 2 females,ranging in age from 25 to 62 years old,with an average age of（46.4±10.3）years old,including 4 patients with atlas fracture/dislocation and 3patients with axis fracture.There were 9 males and 4 females in the study group,with an age range of 28 to 76 years,and an average age of（42.4±11.5）years,including 7atlas fractures/dislocations and 6 axial fractures.The operation time,intraoperative blood loss,and fluoroscopy times were collected and compared between the two groups,and the preoperative and postoperative neck and shoulder pain visual analog scale（VAS）,the Japanese Orthopaedic Association neck nerve function score（JOA）,Spinal cord injury score（ASIA）,three-dimensional CT examination of cervical spine was performed in all patients after operation,and the accuracy of pedicle screw placement was judged according to the evaluation method of Kawaguchi et al.Result Both the guide plate group and the control group completed the operation successfully.The operation was completed by the same group of spine surgery team.There were no obvious complications such as blood vessel and nerve injury during the operation.The postoperative imaging examination showed that the position of the screw rod was good,and no screw extraction was found.out,breakage,etc.A total of 46 atlantoaxial vertebral arch screws were implanted in 13 patients with the aid of 3D printed guides,of which 37 screws were grade 0,8 screws were grade 1,1 screw was grade 2,and no screws were grade 3.In 7 patients,a total of 21 atlantoaxial vertebral arch screws were placed using the traditional screw placement method,of which 12 screws were grade 0,5 screws were grade 1,4 screws were grade 2,and no screws were grade 3.By comparison,it was found that the screw placement accuracy of the guide plate group was higher than that of the traditional fixation group,and the difference was statistically significant（P<0.05）.The operation time（[100.77±26.21] minutes）,intraoperative blood loss（[149.23±63.83]ml）and intraoperative fluoroscopy times（[17.38±9.52] times）of the guide group were significantly less than those of the control group（[146.43±48.88] minutes,[285.71±174.91] ml,[29.71±15.02] times）were significantly different（P<0.05）.The VAS,JOA and ASIA scores of the two groups at 1week after operation and at the last follow-up were significantly improved compared with those before operation（P<0.05）.However,there was no significant difference in the VAS,JOA and ASIA scores before surgery,1 week after surgery and last follow-up between the two groups（P>0.05）.Conclusion 3D printing personalized navigation template-assisted pedicle screw placement is a safe,effective and accurate method.Compared with the traditional manual screw placement method,it can effectively reduce intraoperative blood loss,shorten the operation time,and improve the safety of screw placement.sex and accuracy.The use of 3D printed navigation templates to assist the placement of pedicle screws in patients with upper cervical spine fracture/dislocation has important clinical value and is worthy of further clinical research and use. |
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